[alpaca128]

What kind of definition or distinction do you apply for deciding what is meat?

Because I personally struggle to find a reason for why fish should be an exception, and at least Wikipedia also defines meat as "animal flesh that is eaten as food".

[vkou]

Many cultures draw a clear dietary distinction between between meat, bird, and fish (With 'meat' specifically referring to mammal flesh).

[alpaca128]

Based on what reasoning? Do they also consider whales as source of meat as they're mammals?

[vkou]

Usually cost and availability. Poultry and (if near water) fish are a fairly regular part of the diet, whereas meat, due to its cost is something for the well-off, or special occasions.